CN219267677U - Circuit substrate, LED display device and light-emitting element - Google Patents

Abstract

The utility model provides a circuit substrate, an LED display device and a light-emitting element. The first heat absorption layer and the second heat absorption layer are arranged to absorb laser light with different wavelengths and transmit the energy of the absorbed laser light to the welding electrode, so that the metal of the welding electrode is heated and melted. The first heat absorption layer and the second heat absorption layer can accurately heat the first welding electrode or the second welding electrode, and the mutual influence between the first welding electrode and the second welding electrode is avoided. The circuit substrate structure is convenient for maintenance of the Micro LED chip, and has simple structure and low manufacturing cost.

Description

Circuit substrate, LED display device and light-emitting element

Technical Field

The utility model relates to the technical field of semiconductor devices, in particular to a circuit substrate, an LED display device and a light-emitting element.

Background

LEDs are widely regarded as having high luminous efficiency, long service life, safety, reliability, environmental protection and energy saving, wherein micro LEDs are generally used for display screens. The biggest difference between Micro LED display screen and LCD/OLED display screen is the combination mode of LCD and OLED light emitting device and TFT backboard. The LCD is a combination of a backlight source and a liquid crystal switch, and the OLED is an organic light emitting material attached to a TFT back plate to which a voltage/current is applied through TFT back plate electrodes. The Micro LED display screen is characterized in that Micro LED chips are electrically connected to the TFT backboard electrode by means of different welding modes, and then voltage/current is given to the Micro LED chips through the TFT backboard to emit light.

The biggest difficulty of Micro LED display screen lies in that Micro LED chip is to be made on another carrier, again through huge transfer with a large number of transfer with chip once on the TFT backplate. This is very different from the OLED fabrication process, which is to fabricate the light emitting material directly on the TFT backplane. The difference of the two processes enables the combination mode of the Micro LED light-emitting device and the TFT backboard to directly influence the yield of the display screen, and the Micro LED repair process is particularly important.

The conventional LED chip is electrically connected to the PCB/TFT back plate by soldering the LED chip and the PCB/TFT back plate with solder paste. In order to repair the LED chip rapidly, the technology of removing the LED chip by laser is developed one by one, and the technology utilizes laser energy to excite organic materials in the solder paste, so that the temperature of the solder paste is increased after the solder paste absorbs the laser energy, and the LED chip is taken up after the solder paste is melted. And then, the LED chip is re-welded on the PCB/TFT backboard by adopting the same laser process technology. However, micro LED chips cannot be soldered to a substrate by solder paste, and thus the conventional process described above cannot be adopted.

Therefore, a technology capable of effectively removing the micro LED chip is urgently required.

Disclosure of Invention

In view of the limitation of removing Micro LED chips in the prior art, the utility model provides a circuit substrate, an LED display device and a light emitting element. And a heat absorption layer is arranged below or around the welding electrode of the circuit substrate, and can effectively absorb laser heat, and the welding electrode is heated after absorbing heat, so that the welding electrode is melted, and the LED chip can be conveniently removed.

According to an embodiment of the present utility model, there is provided a circuit substrate including:

an insulating substrate;

the circuit layer is arranged on the insulating substrate and comprises a die bonding area, the die bonding area is provided with a welding electrode used for welding the LED chip, and the welding electrode comprises a first welding electrode and a second welding electrode serving as a repairing bonding pad;

the heat absorption layer comprises a first heat absorption layer and a second heat absorption layer, the first heat absorption layer and the second heat absorption layer are used for absorbing laser with different wavelengths, and the first heat absorption layer and the second heat absorption layer are respectively contacted with the first welding electrode and the second welding electrode and are used for conducting absorbed heat to the welding electrode.

Optionally, the first welding electrode and the second welding electrode are arranged side by side at intervals, the first heat absorbing layer is arranged around the first welding electrode, the second heat absorbing layer is arranged around the second welding electrode, the first heat absorbing layer and the second heat absorbing layer are arranged side by side, or the first heat absorbing layer is arranged below and around the first welding electrode, the second heat absorbing layer is arranged below and around the second welding electrode, and the first heat absorbing layer and the second heat absorbing layer are arranged side by side.

Optionally, the second heat sink layer, the second welding electrode, the first heat sink layer and the first welding electrode are stacked in sequence along a direction from the insulating substrate to the circuit layer.

Optionally, the projection area of the second heat absorbing layer on the circuit substrate > the projection area of the second welding electrode on the circuit substrate > the projection area of the first heat absorbing layer on the circuit substrate > the projection area of the first welding electrode on the circuit substrate.

Optionally, the second heat absorbing layer, the second welding electrode, the first heat absorbing layer and the first welding electrode which are sequentially stacked form a first stack and a second stack which are mutually spaced, and one side opposite to the first stack and the second stack is a flush side wall.

Optionally, the first welding electrode and the first heat sink layer are removed when the light emitting element for repair is welded using the second welding electrode.

Optionally, the melting point of the first welding electrode is lower than the melting point of the second welding electrode.

Optionally, the thickness of the first heat absorbing layer is between 0.5 μm and 5 μm, and the thickness of the second heat absorbing layer is between 0.5 μm and 5 μm.

According to another embodiment of the present utility model, there is provided an LED display device including a circuit substrate; and an LED chip soldered on the circuit substrate, wherein the circuit substrate comprises the circuit substrate provided by the application.

According to still another embodiment of the present utility model, there is provided a light emitting element including:

a light emitting structure having a light emitting surface;

the electrode structure is arranged on the back surface of the light emitting structure, which is far away from the light emitting surface, and is electrically connected with the light emitting structure;

and a heat absorbing layer formed on the back surface of the light emitting structure and surrounding the electrode structure, the heat absorbing layer absorbing heat of the laser light and conducting the absorbed heat to the electrode structure.

Optionally, the heat absorbing layer includes at least one heat absorbing layer, and when the heat absorbing layer includes two or more heat absorbing layers, a plurality of heat absorbing layers are sequentially stacked on the back surface of the light emitting structure.

Optionally, the heat absorbing layer includes a third heat absorbing layer and a fourth heat absorbing layer, the third heat absorbing layer and the fourth heat absorbing layer are used for absorbing laser light with different wavelengths, the electrode structure includes a first electrode and a second electrode, the third heat absorbing layer is formed on one side of the back surface where the first electrode is located, the fourth heat absorbing layer is formed on one side of the back surface where the second electrode is located, and the third heat absorbing layer and the fourth heat absorbing layer form a continuous structure.

Optionally, the third heat absorbing layer is further formed on a first sidewall of the light emitting structure at one side of the first electrode, and the fourth heat absorbing layer is further formed on a second sidewall of the light emitting structure at one side of the second electrode.

As described above, the circuit board, LED display device, and light emitting element of the present utility model have the following advantageous effects:

the utility model provides a heat absorption layer around a welding electrode of a circuit substrate, wherein the heat absorption layer comprises a first heat absorption layer and a second heat absorption layer, and the first heat absorption layer and the second heat absorption layer are respectively contacted with the first welding electrode and the second welding electrode of the welding electrode. The first heat absorption layer and the second heat absorption layer are arranged to absorb laser light with different wavelengths and transmit the energy of the absorbed laser light to the welding electrode, so that the metal of the welding electrode is heated and melted. When a main light-emitting element such as an LED chip is welded and removed, the first heat absorption layer is irradiated by laser with a first wavelength so that metal of the first welding electrode is heated and melted, and the welding and the removal of the LED chip are completed; and when the LED chip is repaired by welding, the second heat absorption layer is irradiated by adopting laser with a second wavelength so that the metal of the second welding electrode is heated and melted, and the welding of the LED chip is completed. The first heat absorption layer and the second heat absorption layer can accurately heat the first welding electrode or the second welding electrode, and the mutual influence between the first welding electrode and the second welding electrode is avoided. In addition, the melting point of the first welding electrode is lower than that of the second welding electrode, so that the integrity of the second welding electrode is not damaged when the main light-emitting element is welded, and the yield of the repairing light-emitting element welded on the second welding electrode is guaranteed. The circuit substrate structure is convenient for maintenance of the Micro LED chip, and has simple structure and low manufacturing cost.

In addition, the positional relationship between the heat sink and the bonding electrode in the circuit substrate and the shape and structure thereof may be varied, for example, the first heat sink and the second heat sink are arranged side by side with the first bonding electrode and the second bonding electrode, or the second heat sink, the second bonding electrode, the first heat sink and the first bonding electrode are stacked in this order in a direction away from the circuit substrate. The heat absorption layer and the welding electrode are variously arranged, adjustment can be made according to actual needs, and the design of the circuit substrate is flexible and various. When the second heat absorption layer, the second welding electrode, the first heat absorption layer and the first welding electrode are overlapped, the first welding electrode and the first heat absorption layer are made of materials which are easy to remove, so that the integrity of the second heat absorption layer and the second welding electrode is not affected by the removal of the first welding electrode and the first heat absorption layer. Meanwhile, the stacking structure is beneficial to reducing the size of the die bonding area, and further beneficial to wiring arrangement of the circuit layer.

And forming a heat absorption layer on the back surface of the light emitting structure of the light emitting element, wherein the heat absorption layer can transfer the heat of the absorbed laser to the electrode structure, so that the electrode structure is heated and melted and then welded to the circuit substrate when being cooled. The arrangement of the heat absorbing layer makes the heating of the electrode structure of the light emitting structure easier to realize, and the heat absorbed by the heat absorbing material can be different by adopting laser irradiation of different wavelengths, so that the light emitting element is suitable for different welding processes, such as a primary welding process as a main light emitting element and a repair welding process as a repair light emitting element.

Drawings

Fig. 1 is a schematic structural diagram of a circuit substrate in the prior art.

Fig. 2a is a schematic structural diagram of a circuit substrate according to an embodiment of the utility model.

Fig. 2b is a schematic structural diagram of a circuit substrate in an alternative embodiment of the first embodiment.

Fig. 3 is a schematic top view of the circuit substrate shown in fig. 2a and 2 b.

Fig. 4 is a schematic structural diagram of a circuit substrate according to a second embodiment of the utility model.

Fig. 5 is a schematic top view of the circuit substrate shown in fig. 4.

Fig. 6 is a schematic structural diagram of an LED display device according to a third embodiment of the present utility model.

Fig. 7 shows a cross-sectional view along the line L1-L1 in fig. 6.

Fig. 8 shows a cross-sectional view along line L1-L1 of fig. 6 in an alternative embodiment.

Fig. 9 is a schematic structural diagram of a light emitting device according to a fourth embodiment of the present utility model.

Fig. 10 is a schematic bottom view of the light emitting device shown in fig. 9.

Fig. 11 is a schematic structural view of a light-emitting element according to a fifth embodiment.

Fig. 12 is a schematic structural diagram of a light emitting device according to a sixth embodiment of the present utility model.

Fig. 13 is a schematic structural diagram of a light emitting element according to a seventh embodiment of the present utility model.

Description of element reference numerals

011 PCB backplate 122 second stack

012. Welding electrode 200 display device

013 LED chip 201 LED chip

014. Solder paste 2011 first chip

100. Second chip of circuit substrate 2012

110. Light emitting device of insulating substrate 300

101. Circuit layer 301 luminous structure

1011. First semiconductor layer of die bonding region 3011

102. Insulating layer 3012 second semiconductor layer

103. Active layer of welding electrode 3013

1031. Heat absorbing layer of first welding electrode 302

1031-1 first positive welding electrode 3021 third heat sink

1031-2 first negative welding electrode 3022 fourth heat sink

1032. Insulating layer of second welding electrode 303

1032-1 second positive welding electrode 304 electrode structure

1032-2 second negative welding electrode 3041 first electrode

104. Heat absorbing layer 3042 second electrode

1041. First heat sink layer 305 via

1042. Light-emitting surface of the second heat-absorbing layer 310

121. Back of the first stack 320

Detailed Description

Other advantages and effects of the present utility model will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present utility model with reference to specific examples. The utility model may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present utility model.

As shown in fig. 1, taking a PCB back plate as an example, a conventional LED chip 013 is soldered to a soldering electrode 012 of the PCB back plate 011 through a solder paste 014, thereby achieving fixation and electrical connection of the LED chip 013 and the PCB back plate 011. When the LED chip is damaged or has poor performance, in order to repair the LED chip rapidly, the organic material in the solder paste 014 is excited by the laser energy, so that the temperature of the solder paste is increased after the solder paste absorbs the laser energy, and the LED chip is taken up after the solder paste is melted. And then, the LED chip is re-welded on the PCB/TFT backboard by adopting the same laser process technology. However, micro LED chips cannot be soldered to a substrate by solder paste, and thus the conventional process described above cannot be adopted.

Example 1

In view of the above-described drawbacks of the prior art, the present embodiment provides a circuit substrate 100 for soldering LED chips, preferably micro LED chips having a size of less than 75 μm. As shown in fig. 2a, the circuit substrate 100 of the present embodiment includes an insulating substrate 110 and a circuit layer 101 disposed on the insulating substrate 110, wherein the circuit layer 101 includes a die bonding region 1011, and the die bonding region 1011 has a bonding electrode 103 for bonding an LED chip. The bonding electrode 103 realizes the fixation of the LED chip on the circuit substrate 100 and the electrical connection with the wiring layer 101. Referring to fig. 2a and 3, the circuit substrate 100 further includes a heat sink layer 104, the heat sink layer 104 being in contact with the bonding electrode 103 for conducting the absorbed heat to the bonding electrode 103.

As shown in fig. 2a, the bonding electrode 103 includes a first bonding electrode 1031 for bonding an LED chip as a main light emitting element and a second bonding electrode 1032 as a repair electrode for bonding a repair LED chip for replacing the main light emitting element. Preferably, the melting point of the first welding electrode 1031 is lower than the melting point of the second welding electrode 1032, thereby ensuring that the second welding electrode 1032 does not melt or soften when the first welding electrode 1031 is melted by heating, ensuring the integrity of the second welding electrode 1032. Specifically, as shown in fig. 2a, the first welding electrode 1031 and the second welding electrode 1032 are disposed side by side with a space therebetween. As shown in fig. 2a, the first welding electrode 1031 includes a first positive welding electrode 1031-1 and a first negative welding electrode 1031-2 for welding the positive and negative electrodes of the LED chip, and the second welding electrode 1032 includes a second positive welding electrode 1032-1 and a second negative welding electrode 1031-2 for welding the positive and negative electrodes of the LED chip, so that, in an alternative embodiment, the first positive welding electrode 1031-1 and the second positive welding electrode 1032-1 are adjacent, the first negative welding electrode 1031-2 and the second negative welding electrode 1031-2 are adjacent, wherein the first positive welding electrode 1031-1 and the second positive welding electrode 1032-1 are disposed insulated from the first negative welding electrode 1031-2 and the second negative welding electrode 1031-2, thus forming a side-by-side structure as shown in fig. 2 a.

Also as shown in fig. 2a, in this embodiment, the heat sink 104 is located around the welding electrode 103. Specifically, the heat absorbing layer 104 is a laser absorbing material, and includes a first heat absorbing layer 1041 and a second heat absorbing layer 1042, where the first heat absorbing layer 1041 and the second heat absorbing layer 1042 are configured to absorb laser light with different wavelengths, so as to generate unequal amounts of energy. In an alternative embodiment, the heat absorbing layer 104 may be a laser absorbing resin, to which a laser absorber is added, which aids in the absorption of laser light and converts the absorbed laser light into heat.

As shown in fig. 2a and 3, a first heat sink 1041 is disposed around the first welding electrode 1031, and a second heat sink 1042 is disposed around the second welding electrode 1032. Specifically, a first heat sink 1041 is disposed about the first positive welding electrode 1031-1 and the first negative welding electrode 1031-2, respectively, and a second heat sink 1042 is disposed about the second positive welding electrode 1032-1 and the second negative welding electrode 1031-2, respectively. Optionally, the first and second heat sink layers 1041 and 1042 form a continuous structure around the first and second welding electrodes 1031 and 1032. As shown in fig. 3, the projection of the heat sink 104 onto the insulating substrate 110 is located around the projection of the welding electrode 103 onto the insulating substrate 110 and is in close proximity to the welding electrode 103 to transfer heat to the welding electrode 103.

In an alternative embodiment, the heat sink layer 104 is located below and around the bonding electrode 103, and in this case, in order to electrically connect the bonding electrode 103 and the circuit layer 102, a plurality of through holes may be formed in the heat sink layer 104, and conductive metal may be filled in the through holes. As shown in fig. 2b, the first heat sink 1041 is disposed under and around the first welding electrode 1031, and the second heat sink 1042 is disposed under and around the second welding electrode 1032. Specifically, a first heat sink 1041 is disposed below and around the first positive welding electrode 1031-1 and the first negative welding electrode 1031-2, respectively, and a second heat sink 1042 is disposed below and around the second positive welding electrode 1032-1 and the second negative welding electrode 1031-2, respectively. Optionally, the first and second heat sink layers 1041 and 1042 form a continuous structure around the first and second welding electrodes 1031 and 1032. At this time, as shown in fig. 3, the projected area of the heat sink 104 on the insulating substrate 110 is larger than the projected area of the bonding electrode 103 on the insulating substrate 110.

When the LED chip needs to be soldered or removed at the first soldering electrode 1031, only the first wavelength laser is used to irradiate the heat absorption layer 104 exposed outside the soldering electrode 103, and at this time, the first heat absorption layer 1041 in the heat absorption layer 104 absorbs the energy of the first wavelength laser and generates heat, and then the heat is conducted to the first soldering electrode 1031, so that the metal of the first soldering electrode 1031 is melted by heating, and soldering or removing of the LED chip is achieved. When the LED chip needs to be soldered at the second soldering electrode 1032, only the second wavelength laser is required to be irradiated to the heat absorption layer 104 exposed outside the soldering electrode 103, and at this time, the second heat absorption layer 1042 in the heat absorption layer 104 absorbs the energy of the second wavelength laser and heats, and then the heat is conducted to the second soldering electrode 1032, so that the metal of the second soldering electrode 1032 is melted by heating, and the soldering of the LED chip is realized. As can be seen, the heat absorption layer 104 of this embodiment can heat the first welding electrode 1031 or the second welding electrode 1032 as required, so as to facilitate welding and repairing of the LED chip.

In an alternative embodiment, the thickness of the heat sink layer 104 is less than the height of the welding electrode 103, e.g. the thickness of the heat sink layer 104 is between 0.5 μm and 5 μm and the thickness of the welding electrode 103 is between 20 μm and 30 μm. The arrangement is that the welding electrode 103 is higher than the heat absorption layer 104, so that the subsequent heat absorption layer 104 is convenient for transmitting energy to the welding electrode 103, and the welding electrode 103 after being exposed and melted is not influenced, so that the LED chip is welded after the metal of the welding electrode 103 is melted.

As shown in fig. 2a and 2b, the circuit substrate 100 further includes an insulating layer 102, and the insulating layer 102 is formed above the circuit layer 101 to protect the circuit layer 101. Meanwhile, the insulating layer 102 exposes the welding electrode 103 and the heat absorbing layer 104 in the region where the welding electrode 103 is located. In an alternative embodiment, the circuit substrate 100 may be a PCB (printed circuit board ), TFT (thin film transistor, thin film transistor) substrate. When the circuit board 100 is a PCB board, it may be a single-layer board or a multi-layer composite board.

Example two

The present embodiment also provides a circuit substrate 100 for soldering LED chips, preferably micro LED chips having a size of less than 75 μm. As shown in fig. 4, the circuit substrate 100 of the present embodiment includes an insulating substrate 110 and a circuit layer 101 disposed on the insulating substrate 110, wherein the circuit layer 101 includes a die bonding region 1011, and the die bonding region 1011 has a bonding electrode 103 for bonding an LED chip. The bonding electrode 103 realizes the fixation of the LED chip on the circuit substrate 100 and the electrical connection with the wiring layer 101. As shown in fig. 4, the circuit substrate 100 also includes a heat sink layer 104, and the heat sink layer 104 is in contact with the bonding electrode 103 for conducting the absorbed heat to the bonding electrode 103.

The difference between this embodiment and the first embodiment is that the heat absorbing layer 104 and the welding electrode 103 are disposed differently, specifically:

as shown in fig. 4, in the present embodiment, the second heat sink 1042, the second bonding electrode 1032, the first heat sink 1041 and the first bonding electrode 1031 are sequentially stacked on the insulating substrate 110 in a direction away from the circuit substrate 100, i.e., in a direction from the insulating substrate to the wiring layer. The second heat sink 1042, the second positive welding electrode 1032-1, the first heat sink 1041 and the first positive welding electrode 1031-1 form the first stack 121, the second heat sink 1042, the second negative welding electrode 1032-2, the first heat sink 1041 and the first negative welding electrode 1031-2 form the second stack 122, the first stack 121 and the second stack 122 are disposed at intervals, and the opposite side walls of the first stack 121 and the second stack 122 are flush structures, and the distant side walls are formed in a ladder structure. Specifically, as shown in fig. 5, the projected area of the second heat sink 1042 on the circuit substrate 100 > the projected area of the second bonding electrode 1032 on the circuit substrate 100 > the projected area of the first heat sink 1041 on the circuit substrate 100 > the projected area of the first bonding electrode 1031 on the circuit substrate 100. Thus, the second heat sink 1042 is made to extend to the outside of the second welding electrode 1032 in all of the three sidewall directions outside the sidewall of the flush structure, the second welding electrode 1032 is made to extend to the outside of the first heat sink 1041 in all of the three sidewall directions outside the sidewall of the flush structure, and the first heat sink 1041 is made to extend to the outside of the first welding electrode 1031 in all of the three sidewall directions outside the sidewall of the flush structure, thereby not affecting the laser irradiation heat sink 104.

When the LED chip needs to be soldered at the first soldering electrode 1031, only the first wavelength laser is required to be irradiated to the heat absorption layer 104 exposed outside the soldering electrode 103, and at this time, the first heat absorption layer 1041 in the heat absorption layer 104 absorbs the energy of the first wavelength laser and generates heat, and then the heat is conducted to the first soldering electrode 1031, so that the metal of the first soldering electrode 1031 is melted by heating, and the soldering of the LED chip is realized. In an alternative embodiment, the first heat sink 1041 and the first bonding electrode 1031 are made of materials that are easy to remove, and when repairing the LED chip, the LED chip on the first bonding electrode 1031 needs to be removed first, and then the LED chip is bonded at the second bonding electrode 1032. At this time, first, laser light of a first wavelength is irradiated to the heat absorption layer 104 exposed to the outside of the bonding electrode 103, and at this time, the first heat absorption layer 1041 in the heat absorption layer 104 absorbs energy of the laser light of the first wavelength and heats up, and then the heat is conducted to the first bonding electrode 1031, so that the metal of the first bonding electrode 1031 is melted by heating, and the LED chip is removed. Then, the remaining first welding electrode 1031 is removed and the first heat absorbing material is removed, then, the laser with the second wavelength is irradiated to the heat absorbing layer 104 exposed outside the welding electrode 103, at this time, the second heat absorbing layer 1042 in the heat absorbing layer 104 absorbs the energy of the laser with the second wavelength and generates heat, and then, the heat is conducted to the second welding electrode 1032, so that the metal of the second welding electrode is melted by heating, and the welding of the LED chip is realized.

Optionally, the thickness of the first heat sink layer 1041 is between 0.5 μm and 5 μm, the thickness of the second heat sink layer 1042 is between 0.5 μm and 5 μm, and the thicknesses of the first heat sink layer 1041 and the second heat sink layer 1042 may be the same or different. The first welding electrode 1031 has a thickness of 10 μm to 20 μm and the second welding electrode 1032 has a thickness of 20 μm to 30 μm. The thickness of the first welding electrode 1031 and the first heat sink 1041 are set so that the first welding electrode 1031 and the first heat sink 1041 are removed, and after the LED chips are welded on the second welding electrode 1032, the heights of the LED chips at the first welding electrode 1031 and the second welding electrode 1032 are not affected, that is, the overall flatness of the display device is not affected.

In addition, in order to achieve the electrical connection of the stacked first and second bonding electrodes 1031 and 1032 with the wiring layer 101, a through hole may be formed in the heat sink layer 104, and a conductive metal may be filled in the through hole so as to communicate the first bonding electrode 1031 with the wiring layer 101, and the second bonding electrode 1032 with the wiring layer 101.

In this embodiment, the heat absorbing layer 104 and the welding electrode 103 are disposed to reduce the area of the die bonding region 1011, thereby facilitating the wiring arrangement of the circuit layer 101. In addition, the first welding electrode 1031 and the first heat-absorbing layer 1041 are made of materials easy to remove, so that the removal of the materials does not affect the integrity of the second heat-absorbing layer 1042 and the second welding electrode 1032, and the yield of the repair process is ensured.

Example III

The present embodiment provides a display device, as shown in fig. 6, the display device 200 of the present embodiment includes a circuit substrate 100 and a plurality of LED chips 201. The circuit substrate 100 is the circuit substrate 100 provided in the first embodiment or the second embodiment of the present application, and reference may be made to the description of the first embodiment and the second embodiment. The LED chip 201 is preferably a micro LED chip having a size of less than 75 μm, and the LED chip 201 includes a light emitting epitaxial layer and an electrode (not shown). The light emitting epitaxial layer includes a first semiconductor layer 3011 (e.g., an N-type GaN layer), an active layer 3013 (e.g., an instra 1-sN/A1GaN multiple quantum well layer) over the first semiconductor layer 3011, and a second semiconductor layer 3012 (e.g., a P-type GaN layer) over the active layer 3013. The min LED chip has a small size and no substrate, so that when the min LED chip is arranged on the circuit substrate 100, the electrode is welded with the welding electrode 103 of the circuit substrate 100 by adopting a metal welding mode, and the electrical connection between the LED chip 201 and the circuit substrate 100 is realized.

As shown in fig. 6, a plurality of LED chips 201 are arranged in an array on the circuit substrate 100, and the plurality of LED chips 201 may be arranged on the circuit substrate 100 in various suitable or desired forms. The plurality of LED chips 201 includes a first chip 2011 serving as a main light emitting element disposed at a first bonding electrode 1031 and at least one second chip 2012 serving as a repair light emitting element disposed at a second bonding electrode 1032.

As shown in fig. 7, in an alternative embodiment of the present embodiment, the circuit substrate 100 is a circuit substrate 100 provided in the first embodiment of the present application. The first chip 2011 is located at the first welding electrode 1031, and since the first heat-absorbing layer 1041 is disposed around the first welding electrode 1031 of the circuit substrate 100, when the first chip 2011 is welded, the first heat-absorbing layer 1041 is irradiated with laser light having a first wavelength, the first heat-absorbing layer 1041 absorbs heat of the laser energy conversion layer and transfers the heat to the first welding electrode 1031, so that the first welding electrode 1031 is heated and melted, an electrode of the first chip 2011 is placed on the first welding electrode 1031, and the first welding electrode 1031 is cooled and solidified to realize fixed welding of the first chip 2011.

When the damaged or malfunctioning first chip 2011 occurs in the display device 200, after the damaged or malfunctioning first chip 2011 is found, the first heat-absorbing layer 1041 at the periphery of the first welding electrode 1031 is irradiated with the laser light with the first wavelength, and the first heat-absorbing layer absorbs the laser energy to be converted into heat, and the heat is conducted to the first welding electrode 1031, so that the first welding electrode 1031 melts, and the first chip 2011 can be removed quickly. And then, the second heat absorbing layer 1042 is irradiated by the laser with the second wavelength, the second heat absorbing layer 1042 absorbs the heat of the laser energy conversion layer and transfers the heat to the second welding electrode 1032, so that the second welding electrode 1032 is heated and melted, the electrode of the second chip 2012 is placed on the second welding electrode 1032, and the second welding electrode 1032 is cooled and solidified to realize the fixed welding of the second chip 2012.

As shown in fig. 8, in another alternative embodiment of the present embodiment, the circuit substrate 100 is a circuit substrate 100 provided in the first embodiment of the present application. The first chip 2011 is located at the first welding electrode 1031, and since the welding electrode 103 and the heat absorbing layer 104 on the circuit substrate 100 are stacked, when the first chip 2011 is welded, the first heat absorbing layer 1041 located below the first welding electrode 1031 is irradiated by laser with a first wavelength, the first heat absorbing layer 1041 absorbs heat of the laser energy conversion layer and transfers the heat to the first welding electrode 1031, so that the first welding electrode 1031 is heated and melted, the electrode of the first chip 2011 is placed on the first welding electrode 1031, and the first welding electrode 1031 is cooled and solidified to realize fixed welding of the first chip 2011.

When the damaged or malfunctioning first chip 2011 occurs in the display device 200, after the damaged or malfunctioning first chip 2011 is found, the first heat-absorbing layer 1041 under the first welding electrode 1031 is irradiated with the laser light with the first wavelength, and the first heat-absorbing layer absorbs the laser energy to be converted into heat, and conducts the heat to the first welding electrode 1031, so that the first welding electrode 1031 melts, and the first chip 2011 can be removed rapidly. After the first chip 2011 is removed, the remaining first bonding electrode 1031 is removed and the first heat sink layer 1041 is removed.

And then, the second heat absorbing layer 1042 is irradiated by the laser with the second wavelength, the second heat absorbing layer 1042 absorbs the heat of the laser energy conversion layer and transfers the heat to the second welding electrode 1032, so that the second welding electrode 1032 is heated and melted, the electrode of the second chip 2012 is placed on the second welding electrode 1032, and the second welding electrode 1032 is cooled and solidified to realize the fixed welding of the second chip 2012.

In addition, the display device 200 of the present embodiment further includes a bottom case and a cover, and a power module (not shown in detail), between which the circuit substrate 100 is sandwiched, and the cover and the bottom case are fixed to each other to form a cavity accommodating the circuit substrate 100 and the LED chip 201. The power module may also be disposed in the cavity formed by the bottom case and the cover, and the power module is connected to the circuit substrate 100 and an external power source to supply power to the LED chip 201 in the display device 200.

Example IV

The present embodiment provides a light emitting device, as shown in fig. 9, the light emitting device 300 includes a light emitting structure 301, an electrode structure 304 and a heat sink layer 302, wherein the light emitting structure 301 has a light emitting surface 310 and a back surface 320 opposite to the light emitting surface 310. The electrode structure 304 is formed on the back surface 320 of the light emitting structure 301 and is electrically connected to the light emitting structure 301.

In order to ensure electrical connection between the electrode structure 304 and the light emitting structure 301, as shown in fig. 10, a plurality of through holes 305 may be formed in the heat absorbing layer 302 at positions corresponding to the electrode structure 304, and conductive metal may be filled in the through holes 305 to electrically connect the electrode structure 304 and the light emitting structure 301. Meanwhile, in order to ensure the performance of the heat sink 302 without affecting the light emitting performance and thickness of the light emitting device 300, in this embodiment, the thickness of the heat sink 302 is between 0.5 μm and 5 μm.

In this embodiment, the heat absorbing layer 302 is a single-layer structure, and the heat absorbing layer 302 is made of a laser absorbing material, for example, may be a laser absorbing resin, to which a laser absorber is added, and the laser absorber facilitates absorption of laser light and converts the absorbed laser light into heat. The heat absorption layer 302 absorbs laser light with a certain wavelength and generates heat, and the heat is transferred to the electrode structure 304, so that the metal layer of the electrode structure 304 is melted by heating, and the light emitting element 300 is welded or removed. For example, in the present embodiment, as shown in fig. 9, when the light emitting element 300 is to be welded, the heat absorbing layer 302 is irradiated with laser light having a certain wavelength, the heat absorbing layer 302 absorbs the laser light and generates heat, the heat is transferred to the electrode structure 304 so that the metal layer of the electrode structure 304 is melted, the light emitting element 300 is placed at the welding position, and during the cooling process, the melted metal layer is solidified to weld and fix the light emitting element 300 to the welding position. When the light emitting device 300 needs to be removed, the heat absorbing layer 302 is also irradiated with laser light having a certain wavelength, and the heat absorbing layer 302 absorbs the laser light and generates heat, and the heat is transferred to the electrode structure 304 to melt the metal layer of the electrode structure 304, so as to facilitate removal of the light emitting device 300.

As also shown in fig. 9, the light emitting structure 301 includes a first semiconductor layer 3011, a second semiconductor layer 3012, and an active layer 3013 located between the first semiconductor layer 3011 and the second semiconductor layer 3012, the active layer 3013 being a light emitting layer of the light emitting structure 301. Alternatively, the first semiconductor layer 3011 may be an N-type semiconductor layer, and the second semiconductor layer 3012 may be a P-type semiconductor layer, and it is understood that a transparent conductive layer or the like may be formed over the second semiconductor layer 3012. Of course, the first semiconductor layer 3011 may be a P-type semiconductor layer, and the second semiconductor layer 3012 may be an N-type semiconductor layer. In an alternative embodiment, the first semiconductor layer 3011 may be an n-type GaN layer, the active layer 3013 may be a quantum well layer, and the second semiconductor layer 3012 may be a p-type GaN layer. Alternatively, the first semiconductor layer 3011 may be an n-type GaN layer, the active layer 3013 may be an InGaN/GaN multiple quantum well, and the second semiconductor layer 3012 may be a p-type GaN layer. The electrode structure 304 includes a first electrode 3041 and a second electrode 3042, wherein the first electrode 3041 is electrically connected to the first semiconductor layer 3011, and the second electrode 3042 is electrically connected to the second semiconductor layer 3012. It can be understood that, in order to realize that the light emitting element 300 emits light from the light emitting surface 310, a reflective structure is further formed on the back surface 320 of the light emitting structure 301.

As shown in fig. 9, the surface of the light emitting structure 301 is further formed with an insulating layer 303, and the insulating layer 303 is formed on the surface of the light emitting structure 301 or on the surface and the sidewall of the light emitting structure 301 to protect the light emitting element 300.

The heat sink 302 on the light emitting element 300 is configured to facilitate heating the electrode structure 304 and facilitate soldering of the light emitting element 300.

Example five

The present embodiment provides a light emitting device, as shown in fig. 11, the light emitting device 300 includes a light emitting structure 301, an electrode structure 304 and a heat sink layer 302, wherein the light emitting structure 301 has a light emitting surface 310 and a back surface 320 opposite to the light emitting surface 310. The electrode structure 304 is formed on the back surface 320 of the light emitting structure 301 and is electrically connected to the light emitting structure 301. The difference from the fourth embodiment is that:

in this embodiment, the heat sink layer 302 on the back surface 320 of the light emitting element 300 has a two-layer or multi-layer structure, and in this embodiment, the heat sink layer 302 includes a third heat sink layer 3021 and a fourth heat sink layer 3022 as shown in fig. 11. The third heat sink layer 3021 and the fourth heat sink layer 3022 are stacked on the back surface 320 of the light emitting element 300. The third heat sink 3021 and the fourth heat sink 3022 are configured to absorb laser light of different wavelengths, thereby generating unequal amounts of heat, and the generated heat may be transferred between the third heat sink 3021 and the fourth heat sink 3022. Thus, when the light emitting element 300 is welded or the light emitting element 300 is removed, the third heat absorbing layer 3021 or the fourth heat absorbing layer 3022 may be irradiated with laser light of different wavelengths, respectively. For example, when the light emitting element 300 is welded, the fourth heat absorbing layer 3022 is irradiated with the laser light having the fourth wavelength, and the heat generated by the absorption of the laser energy by the fourth heat absorbing layer 3022 is transferred to the electrode structure 304, so that the electrode structure 304 is melted, and the welding and fixing of the light emitting element 300 is achieved in the process of cooling and solidifying the electrode structure 304. When the light emitting element 300 needs to be removed, the third heat absorbing layer 3021 is irradiated with the laser light having the third wavelength, and the heat generated by the absorption of the laser energy by the third heat absorbing layer 3021 is transferred to the electrode structure 304 through the fourth heat absorbing layer 3022, so that the electrode structure 304 is melted, and at this time, the light emitting element 300 can be removed rapidly. Or when the light emitting element 300 is welded or removed, the third heat absorbing layer 3021 and the fourth heat absorbing layer 3022 are irradiated with the laser light of the third wavelength and the fourth wavelength at the same time, so that the heat generation and the heat transfer can be accelerated, the laser irradiation time can be saved, and the welding or removing efficiency can be improved.

Example six

The present embodiment provides a light emitting device, as shown in fig. 12, the light emitting device 300 includes a light emitting structure 301, an electrode structure 304 and a heat sink layer 302, wherein the light emitting structure 301 has a light emitting surface 310 and a back surface 320 opposite to the light emitting surface 310. The electrode structure 304 is formed on the back surface 320 of the light emitting structure 301 and is electrically connected to the light emitting structure 301. The difference from the fifth embodiment is that:

as shown in fig. 12, in the present embodiment, the third heat sink 3021 and the fourth heat sink 3022 are respectively located on the back surface 320 of the light emitting structure 301 on the side of the first electrode 3041 and the back surface 320 of the light emitting structure 301 on the side of the second electrode 3042. And the third heat sink layer 3021 and the fourth heat sink layer 3022 form a continuous structure at the rear surface 320 of the light emitting structure 301. The third heat sink layer 3021 and the fourth heat sink layer 3022 are arranged to absorb laser light of different wavelengths, thereby generating unequal amounts of heat, and the generated heat may be transferred between the third heat sink layer 3021 and the fourth heat sink layer 3022. Thus, when the light emitting element 300 is welded or the light emitting element 300 is removed, the third heat absorbing layer 3021 and the fourth heat absorbing layer 3022 may be irradiated with laser light of different wavelengths, respectively. For example, when the light emitting element 300 is welded, the third heat absorbing layer 3021 is irradiated with laser light of a third wavelength, the fourth heat absorbing layer 3022 is irradiated with laser light of a fourth wavelength, the heat generated by absorption of laser energy by the third heat absorbing layer 3021 is transferred to the first electrode 3041 structure, the heat generated by absorption of laser energy by the fourth heat absorbing layer 3022 is transferred to the second electrode 3042 structure, the electrode structure 304 is melted, and the welding and fixing of the light emitting element 300 are achieved during the cooling and solidification of the electrode structure 304. When the light emitting element 300 needs to be removed, the third heat absorbing layer 3021 is irradiated with the laser light of the third wavelength, the fourth heat absorbing layer 3022 is irradiated with the laser light of the fourth wavelength, the heat generated by the absorption of the laser energy by the third heat absorbing layer 3021 is transferred to the first electrode 3041 structure, the heat generated by the absorption of the laser energy by the fourth heat absorbing layer 3022 is transferred to the second electrode 3042 structure, so that the electrode structure 304 is melted, and at this time, the light emitting element 300 can be removed rapidly. Or when the light emitting element 300 is welded or removed, the third heat absorbing layer 3021 is irradiated with a third wavelength, or the fourth heat absorbing layer 3022 is irradiated with a laser of a fourth wavelength, and heat generated by absorption of laser energy by the third heat absorbing layer 3021 or the fourth heat absorbing layer 3022 is transferred between each other and transferred to the electrode structure 304, so that the electrode structure 304 is melted, and welding or removal of the light emitting element 300 is achieved.

Example seven

The present embodiment provides a light emitting device, as shown in fig. 13, the light emitting device 300 includes a light emitting structure 301, an electrode structure 304 and a heat sink layer 302, wherein the light emitting structure 301 has a light emitting surface 310 and a back surface 320 opposite to the light emitting surface 310. The electrode structure 304 is formed on the back surface 320 of the light emitting structure 301 and is electrically connected to the light emitting structure 301. The difference from the sixth embodiment is that:

as shown in fig. 13, in the present embodiment, a third heat sink layer 3021 and a fourth heat sink layer 3022 are also formed on the side wall of the light emitting element 300. Specifically: the third heat sink 3021 extends to the first side wall of the light emitting element 300 on the side of the first electrode 3041, and the fourth heat sink 3022 extends to the second side wall of the light emitting element 300 on the side of the second electrode 3042. The above arrangement of the heat sink 302 increases the area of the heat sink 302, i.e., the area that can be irradiated by laser, so that the heat generation and transfer efficiency can be increased, and the welding and removal efficiency of the light emitting element 300 can be improved. Meanwhile, since the heat sink layer 302 is provided as an insulating material, the light emitting element 300 can be further protected.

The above embodiments are merely illustrative of the principles of the present utility model and its effectiveness, and are not intended to limit the utility model. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the utility model. Accordingly, it is intended that all equivalent modifications and variations of the utility model be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (13)

1. A circuit substrate, comprising:

an insulating substrate;

the circuit layer is arranged on the insulating substrate and comprises a die bonding area, the die bonding area is provided with a welding electrode used for welding the LED chip, and the welding electrode comprises a first welding electrode and a second welding electrode serving as a repairing bonding pad;

the heat absorption layer comprises a first heat absorption layer and a second heat absorption layer, the first heat absorption layer and the second heat absorption layer are used for absorbing laser with different wavelengths, and the first heat absorption layer and the second heat absorption layer are respectively contacted with the first welding electrode and the second welding electrode and are used for conducting absorbed heat to the welding electrode.

2. The circuit substrate of claim 1, wherein the first and second bonding electrodes are disposed side-by-side with a spacing therebetween, the first heat sink layer is disposed about the first bonding electrode, the second heat sink layer is disposed about the second bonding electrode, the first and second heat sink layers are disposed side-by-side with each other, or the first heat sink layer is disposed below and about the first bonding electrode, the second heat sink layer is disposed below and about the second bonding electrode, and the first and second heat sink layers are disposed side-by-side with each other.

3. The circuit substrate according to claim 1, wherein the second heat sink layer, the second bonding electrode, the first heat sink layer, and the first bonding electrode are stacked in this order in a direction from the insulating substrate to the wiring layer.

4. The circuit substrate of claim 3, wherein a projected area of the second heat sink layer on the circuit substrate > a projected area of the second bonding electrode on the circuit substrate > a projected area of the first heat sink layer on the circuit substrate > a projected area of the first bonding electrode on the circuit substrate.

5. The circuit substrate of claim 4, wherein the second heat sink layer, the second bonding electrode, the first heat sink layer, and the first bonding electrode, which are stacked in sequence, form first and second stacks spaced apart from each other, opposite sides of the first and second stacks being flush sidewalls.

6. The circuit substrate of claim 3, wherein the first bonding electrode and the first heat sink layer are removed when the light emitting element for repair is bonded using the second bonding electrode.

7. A circuit substrate according to claim 2 or 3, wherein the melting point of the first bonding electrode is lower than the melting point of the second bonding electrode.

8. The circuit substrate of claim 3, wherein the first heat sink layer has a thickness of 0.5 μm to 5 μm and the second heat sink layer has a thickness of 0.5 μm to 5 μm.

9. An LED display device, comprising:

a circuit substrate; and

an LED chip soldered on the circuit substrate, wherein the circuit substrate comprises the circuit substrate according to any one of claims 1 to 8.

10. A light-emitting element, comprising:

a light emitting structure having a light emitting surface;

the electrode structure is arranged on the back surface of the light emitting structure, which is far away from the light emitting surface, and is electrically connected with the light emitting structure;

and a heat absorbing layer formed on the back surface of the light emitting structure and surrounding the electrode structure, the heat absorbing layer absorbing heat of the laser light and conducting the absorbed heat to the electrode structure.

11. The light-emitting element according to claim 10, wherein the heat sink layer comprises at least one heat sink layer, and when the heat sink layer comprises two or more heat sink layers, a plurality of heat sink layers are stacked on the back surface of the light-emitting structure in this order.

12. The light-emitting element according to claim 10, wherein the heat-absorbing layer comprises a third heat-absorbing layer and a fourth heat-absorbing layer for absorbing laser light of different wavelengths, wherein the electrode structure comprises a first electrode and a second electrode, wherein the third heat-absorbing layer is formed on a side of the back surface on which the first electrode is located, wherein the fourth heat-absorbing layer is formed on a side of the back surface on which the second electrode is located, and wherein the third heat-absorbing layer and the fourth heat-absorbing layer form a continuous structure.

13. The light-emitting element according to claim 12, wherein the third heat sink layer is further formed on a first side wall of the light-emitting structure on the first electrode side, and wherein the fourth heat sink layer is further formed on a second side wall of the light-emitting structure on the second electrode side.

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